Department of Anesthesiology, The Third Xiangya Hospital of Central South University, Changsha 410013, China.
Neurosci Lett. 2012 Jan 11;506(2):240-4. doi: 10.1016/j.neulet.2011.11.015. Epub 2011 Nov 17.
The underlying causes of post-operative cognitive dysfunction (POCD) in elderly patients remain to be elucidated. In order to explore possible contributory mechanisms, we tested the effects of isoflurane anesthesia on (i) expression of hippocampal neuronal nitric oxide synthase (nNOS) and (ii) the relationship of changes in nNOS expression to cognitive dysfunction in isoflurane-treated aged rats. Our results indicate that isoflurane treatment leads to significant changes in correct reactions (F=28.35, p<0.001), initiative avoidances (F=29.33, p<0.001), and total reaction time (TRT) (F=6.99, p<0.05) of treated rats in the Y-maze test. Isoflurane-treated rats had fewer correct reactions and initiative avoidances in the Y-maze test 24 and 48 h after 2 h of isoflurane anesthesia compared with control group rats (p<0.05). TRTs to complete 20 trials of the Y-maze test increased significantly 48 h after 2 h anesthesia. The number of nNOS-positive hippocampal neurons decreased 24 h after anesthesia, corresponding to an increased mean immunostaining grey-scale value. These data show that isoflurane causes a transient decrease in expression of hippocampal nNOS in aged rats during early post-anesthesia stages, and that the transient decrease of nNOS is closely correlated with cognitive impairment in isoflurane-treated aged rats.
术后认知功能障碍（POCD）在老年患者中的根本原因仍不清楚。为了探讨可能的促成机制，我们测试了异氟醚麻醉对（i）海马神经元型一氧化氮合酶（nNOS）表达和（ii）nNOS 表达变化与异氟醚处理老年大鼠认知功能障碍之间关系的影响。我们的结果表明，异氟醚处理导致 Y 迷宫测试中处理组大鼠正确反应（F=28.35，p<0.001）、主动回避（F=29.33，p<0.001）和总反应时间（TRT）（F=6.99，p<0.05）的显著变化。与对照组大鼠相比，2 小时异氟醚麻醉后 24 和 48 小时，异氟醚处理组大鼠在 Y 迷宫测试中的正确反应和主动回避次数减少（p<0.05）。2 小时麻醉后 48 小时，完成 Y 迷宫测试 20 次的 TRT 显著增加。麻醉后 24 小时，海马 nNOS 阳性神经元数量减少，相应的平均免疫染色灰度值增加。这些数据表明，异氟醚在麻醉后早期导致老年大鼠海马 nNOS 表达短暂下降，nNOS 的短暂下降与异氟醚处理老年大鼠的认知障碍密切相关。
